Questions tagged [titration]

A laboratory method to determine the concentration of an analyte in solution. The solution volume plays a key role in the analysis.

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Why rinse flask with distilled water when the flask will be used for storing aliquots of HCl for titration?

In an experiment for standardisation of NaOH with titration, the lab manual instructed students to rinse conical flasks that were supposed to store 1mL aliquots of hydrochloric acid with distilled ...
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264 views

How can you perform an acid-base titration with antacids if substances, like aluminium hydroxide, are insoluble?

I am trying to perform an experiment in order to determine the efficiency of different antacids. An online search later shows that you add an HCl solution in a solution created with a base/antacid. ...
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621 views

Calculate hardness of water

A sample of water has its hardness due to only $\ce{CaSO4}$. When this water is passed through on anion exchange resin, $\ce{SO4^2-}$, the $\ce{SO}$ ions are replaced by $\ce{OH-}$. A 25.0 mL sample ...
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3k views

Calculating the pH of the endpoint in a titration of weak acid and strong base

Show that the pH at the endpoint in the titration of $\mathrm{0.100\ mol\ dm^{-3}}$ ethanoic acid with $\mathrm{0.100\ mol\ dm^{-3}}$ sodium hydroxide is 8.72. The dissociation constant Ka of ethanoic ...
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738 views

Potassium permanganate to analyze iron compounds [closed]

In my lab, I used potassium permanganate in order to analyze the amount of iron in a compound with iron in the +2 oxidation state using titration. My question is how would this analysis be different ...
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99 views

Do Bases and Acids actually react with each other? [closed]

Let's say we have $5$ $\ce{HCl}$ molecules and we dump them into a container full of water. It's a strong acid so all $5$ $\ce{H+}$ ions would react with water and create $\ce{H3O+}$. It reacts with ...
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407 views

What indicators can be used when substituting iodine with other halogens in the Winkler method?

I'm a chemistry student who is doing an investigation with respect to the Winkler method. The Winkler method is one which is used to find the oxygen content in water. Primarily, the halide which is ...
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168 views

Redox reaction KMnO4 + FeX [closed]

Today I was conducting a redox titration with $\ce{MnO4}$ and unknown amount of $\ce{FeX}$ which through qualitative observation looked like $\ce{FeO(s)}$. I titrated the $\ce{FeX}$(which was ...
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130 views

Buffers: what does the strong base react with?

I am a bit confused on buffers: If I have a solution with a weak acid (say $\ce{NH4}$) and its conjugate weak base ($\ce{NH3}$), I have a buffer solution (in $\ce{H2O}$). $$\ce{NH4 <--> NH3 + ...
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What happens to acids/bases left out overnight?

I conducted a titration experiment a few days back and was unable to neutralize the solution in time, so I had to leave the solutions of HCl and NaOH out overnight in order to use them the next day. ...
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Why is finding [H+] when given [OH-]= 3.57e-5 M wrong when I use -log[OH-]?

Question/Problem I know that [H+][OH-]=$10^{-14}$ And the problem asks to find out the concentration of H+ when the concentration of OH- is $3.57*10^{-5}$M By using the equation above i find that ...
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pH Curve in Acid/Base Titrations

So I came across a question on the equation of the pH curve, and I wanted to know how the user here arrived at the matter balance equation. Any help would be appreciated! Here is the question: The ...
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158 views

How to solvethis problem related to redox titration?

A $1.0\ \mathrm{g}$ sample containing $\ce{BaCl2*2H2O}$ was dissolved and an excess of $\ce{K2CrO4}$ solution added. After a suitable period, the $\ce{BaCrO4}$ was filtered, washed and redissolved in $...
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titration of ascorbic acid

In this article. Authors use $\ce{KI}$ in potentiometric titration of ascorbic acid with permanganate and dont describe why! Anyvody know why should we use $\ce{KI}$ in potentiometric titration of ...
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Finding the molarity of an acid in a titration

I was doing a question that asks the molarity of a 10 mL of tartaric acid that is titrated to phenolphthalein endpoint with 20 mL of 1.0 M NaOH. I worked it out by equating the molarity of the NaOH ...
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401 views

Estimation of CO2 by titrimetric method using phenolphthalein indicator

We were estimating dissolved $\ce{CO2}$ in water by American Public Health Association (APHA) method. It was a titrimetric method using phenolphthalein indicator. Titrant used was $\ce{NaOH}$ and ...
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742 views

How does dilution affect result of titration of jam?

We currently do some pH adjustments of jams (target pH of 3.2) using citric acid, however, when there is a large difference between the starting pH and the target pH this can be quite a time consuming ...
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Deriving the equation for oxygen estimation by Winkler’s method

We were doing $\ce{O2}$ estimation by Winkler's method The procedure and reactions involved in this experiment are: Carefully fill a 300-mL glass stoppered bottle brim-full with sample water. ...
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557 views

Use of pipette during experiments for determination of oxygen by Winkler's method

We were performing estimation of $\ce{O2}$ by Winkler's method and we were told by the instructor that while adding $\ce{MnSO4}$ and $\ce{NaOH}$ / $\ce{KI}$ the pipette tip should be well below the ...
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Use of Na2S2O3 before starch in Winkler's method

In Winkler's method why is some amount of $\ce{Na2S2O3}$ added before addition of starch solution turning the deep straw coloured solution pale straw? Is it to generate $\ce{I-}$ ions needed for ...
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362 views

What are the reactions occurring during the titration of a carbon dioxide contaminated water sample with diluted sodium hydroxide solution?

During estimation of dissolved $\ce{CO2}$ in water, we took a water sample, added few drops of phenolphthalein and titrated it against dil $\ce{NaOH}$. Questions What are the reactions that happen: ...
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Should the measurement uncertainty be included in the random uncertainty?

So, the other day I was carrying out a titration and got the titres $33.4cm^3$ and $33.3cm^3$. I calculated the random uncertainty to be $0.05cm^3$. Now, the burette itself had an uncertainty of and I'...
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Reaction of sodium hydroxide with ethanol

I am carrying out a titration to determine the solubility of a carboxylic acid in mixtures of water and ethanol. I will be titrating a diluted (previously) saturated solution of water, ethanol and the ...
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How did early chemists measure concentrations and purity?

My chemistry teacher loves going back through the history of famous chemists. This got me wondering how these chemists would first determine the concentration of a sample before they had any other ...
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How to determine the equivalent weight of CO2

We were estimating dissolved $\ce{CO2}$ in water by American Public Health Association method. It was a titrimetric method using phenolpthalein indicator. Titrant used was $\ce{NaOH}$ and analyte was ...
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89 views

Why do we say there's no carbon dioxide present?

Were were estimating dissolved $\ce{CO2}$ in water by American Public Health Association method. It was a titrimetric method using phenolphthalein indicator. Titrant used was $\ce{NaOH}$ and analyte ...
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1answer
492 views

When does phenolphthalein containing solution change colour? [closed]

We were estimating the amount of dissolved $\ce{CO2}$ in water using the American Public Health Association method. It was a Titrimetric Method using phenolphthalein indicator. Titrant used was $\ce{...
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2k views

How to quantify caffeine content in coffee?

How do I titrate caffeine from coffee to estimate the percentage of caffeine in coffee? I have tried using iodine solution, sulfuric acid, and sodium thiosulfate to no avail.
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How to find the equivalence point on a graph of an acid-base titration curve? [closed]

Here is the data taken from the lab: Acid pH, Vol (cm3)[ (9.67, 4cm3) (9.08, 8cm3) (8.70, 10cm3) (8.06, 12cm3) (7.93, 13cm3) (4.76, 14cm3) (2.45, 15cm3) (2.23, 16cm3) (2.10, 17cm3) (2.01, ...
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EDTA Titrations

I was doing some questions on EDTA titrations and was wondering how you actually derive the second equation here: $$\begin{align} α_{\ce{Y^4-}} &= \frac{[\ce{Y^4-}]}{[\ce{H6Y^2+}] + [\ce{H5Y+}] + ...
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Why do we titrate from a colourless solution and why should we remove unused sodium hydroxide from the burette as soon as possible?

In my lab we performed an acid base titration, where NaOH was used to titrate a standard solution, potassium hydrogen phthalate (KHP, or $\ce{K+C6H4(CO2H)(CO2^-)}$), using phenolphthalein indicator. ...
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Why do universal indicators in titration have to be swirled?

Why do universal indicators in titration have to be swirled? Here's a specific example: I am using methyl orange along with hydrochloric acid to test the alkalinity of a set of household cleaners (...
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326 views

Find second acid dissociation constant at a given pH

In short, the problem states that: We have a molecule that has two ionizable groups $\mathrm{p}K_\mathrm{a,1}$ is between $5.0$ and $9.0$; $\mathrm{p}K_\mathrm{a,2}$ is outside of this range. ...
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Yellowish tinge during titration of oxalic acid with potassium permanganate

One of the our chemistry practicals involve finding the molarity of an oxalic acid solution by titrating it with standard $\ce{KMnO4}$ solution. The oxalic acid solution is heated and little sulfuric ...
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1answer
911 views

How to calculate the concentration of a monoprotic organic acid that was extracted into an ethyl ether layer?

Compound A is a monoprotic organic acid. If $25.0~\mathrm{mL}$ of a $0.456~M$ solution of A in water was extracted with $25.0~\mathrm{mL}$ of ethyl ether and it was determined experimentally that $5....
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Does titration usually always involve neutralization?

I've been doing titration exercises that involve figuring out the molarity of an unknown solution when you know the molarity of another (so like knowing the molarity of solution A but figuring out the ...
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Writing equation of reaction in stoichiometry of redox titrations

While solving some questions on the stoichiometry on redox titrations, I come across this question: Calculate the volume of $0.05\ \mathrm{M} \ \ce{KMnO4}$ solution required to oxidize completely $...
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Equivalence point of titration

Why is $\ce{[HIn] = [In-]}$ at equivalence point of a titration? I know that at equivalence point moles of known solution is equal to the moles of unknown solution, but I'm not able to relate that ...
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Is this problem about acid-base titration wrong?

I wouldn't post mere 'problems' here normally, but I will hopefully be starting to give chemistry education to some 10-11-12th graders and I want to make sure that it is not I that has a problem but ...
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348 views

pH Curves- Anomalies

In class, the other day, we were discussing pH curves. Assume that I have HCl and NaOH of concentration 1 mol/mL. Now, consider that I have 50mL of HCl, and begin adding small quantities of NaOH. I ...
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Standardization of sodium thiosulfate using potassium dichromate

In this process first we need to liberate iodine to react with sodium thiosulfate. First, sodium bicarbonate is added to a iodate-free solution of potassium iodide. The mixture is shaken until the ...
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928 views

Iodine Titration with Free SO2 in wine

To determine the free $\ce{SO2}$ in wine, a common method used is called the Ripper Titration Method. The equation is as follows: $$\ce{SO2 (aq) + I2 (aq) + 2H2O (l) -> 4H+ (aq) + SO4^2- (aq) + ...
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Regarding Kw, titrations, and pH

So I have need of performing a titration upon a fruit juice to determine acid concentration. I will be using 1M NaOH as my base. Seeing as the solution will be coloured, it would be difficult to use ...
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262 views

Do I need to include calcium chloride in this reaction equation?

Yesterday I titrated a solution of calcium hydroxide in aqueous calcium chloride with $16.7~\mathrm{mL}$ of $\ce{HCl}$. More specifically, I took $25\ \mathrm{mL}$ of the calcium hydroxide in aq ...
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2answers
938 views

Can Henderson-Hasselbalch equation be used to determine the pH of a solution when a strong base and a strong salt of that base stay together?

The following problem I have stated was not given to me as a homework. I have found this one in my textbook. I have solved it in my own way, but I'm not sure about the correctness of my procedure. I ...
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1answer
505 views

How much lactose is there in milk (mechanism)?

Iodometric titration is sometimes used to find out how much lactose there is in milk. The overall oxidation reaction is written as follows. $$\ce{C12H22O11 + I2 + 3NaOH ->[\ce{CuSO4}]C12H21O12Na + ...
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Titration of acid with base or base with acid: can I always use the same indicator?

If you are doing a titration with $\ce{NaOH}$ and $\ce{HCl}$, does it matter which one goes in the burette, and will this change the outcome of whether the solution in the beaker will turn pink due to ...
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How to determine the percentage of iron(II) and iron(III) in a solution?

Outline a plan of an experiment to determine the percentage of iron present as iron(III) in a solution containing $\ce{Fe^3+(aq)}$ and $\ce{Fe^2+(aq)}$ ions. You are provided with zinc, a standard ...
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Are titration, recrystallisation, functional group analysis, etc. outdated?

In modern chemistry, - pH meter, ion electrode, AES, HPLC, etc. replacing titration - HPLC replacing recrystallisation - IR and NMR replacing melting point analysis, derivative analysis, functional ...
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371 views

Preparing a 0.030 M solution of potassium ferrocyanide trihydrate?

I am a little bit confused on what I am supposed to do. The instructions say to prepare 250 mL of this solution by measuring out in grams the amount of PFT using a 250 mL volumetric flask. Then it ...